Method of dehydrating oil emulsions



Patented Au 24, 1926.-

UNITED STATES PATENT oFrics.

RALPH A. HALLORAN, 01F BERKELEY, CALIFORNIA, ASSIGNOR T0 STANDARD OIL COMPANY, 015 SAN FRANCISCO, CALIFORNIA, A CORPORATION OF CALIFORNIA.

METHOD OF DEHYDRATING OIL' EMULSIONS.

No Drawing.

This invention relates to a method of demulsifying oil emulsions and refers particularly to a method adapted for the dehydrating of oil and water emulsions of crude mineral oil and water.

A considerable portion of crude oil as it is obtained from the ground is in the form of a water-and-oil emulsion carrying up to as high as 65% to 7 0% water. In order for the proper refinement of such oil, it is necessary that it should be separated from the greater portion of its water. It has been found that emulsion of oil and water such as the normal crude oil emulsions contain negatively charged Water particles surrounded by positively charged oil. It appears that a part of the stability of such emulsions is due to the attraction of these two unlike static charges.

It is an object of the present invention to provide a method of hydrating such emulsions by treatment of the emulsion with an electrolyte having a high hydrogen ion content for neutralizing the static negative charge of the water globules of the emulsion. Neutralization of the static negative charge of the water globules of the emulsion by a hydrogen ion content of an electrolyte eliminates the attraction between the original unlike static charges of the emulsion and thus removes one of the main forces holding the oil and water in an emulsified state. Mere treatment, however, with strong acids such as sulfuric acid having a high hydrogen ion content is unsuited for the dehydration of such emulsions, at least when utilized in commercially feasible amounts.

The electrolyte having the high hydrogen ion content must, in addition, contain a substance mutually soluble in both phases of the emulsion and soluble therein in certain definite proportions if a small quantity of the electrolyte is to be effective for dehydrating the emulsion. It has been found that by proper selection of certain.

acid sludges derived from the sulfuric acid treatment of petroleum oil the process for carrying out such dehydration reaction can be efiected by employing in the proper quantities such acid sludge under other regulated operating conditions,

Acid sludges are obtained in the petroleum refining art from the treatment with sulfuric acid of different mineral oil pro ducts. These sludges are of various classes Application filed June 11, 1925. Serial No. 36,554.

depending upon the kind and gravity of oil treated and the strength of the sulfuric acid used and the temperature of treatment. Generally, these sludges may be classified into two typesthose termed polymerized sludges and those termed sulfonated sludges.

Polymerized sludges are obtained mainly by treatment with weak acids at low temperature and mainly when treating oils of paraffin base, whereas sulfonated sludges are obtained by the treatment with concentrated acids and at high temperature and by the treatment of oil of asphaltic, n-aphthenic or mixed base crudes. Sludges of both classes may be obtained from different crudes, depending, however, upon the strength and temperature of treatment and other factors.

Sulphonic acid sludges which are both oil of a method of treating oil emulsions embodying the invention, for which purpose a detailed example of a practical process will now be described.

The emulsion, such as crude oil emulsion, is first charged into the treater or agitator, preferably one hav ng a cone bottom to facilitate separativm. of the water from the oil after the dehy-"lrating treatment. The crude oil emulsion is heated either before, during, or after charging, to a temperature between 150 and 200 F., preferably to a temperature of 175 F. Other temperatures are found to produce unsatisfactory separation of the emulsion, lower temperatures resulting in improper separation of the mixture and higher temperatures tending to produce excessive loss of gasoline or other low boiling portions of the oil of theemulsion.

Sulfuric acid sludge of the sulfonated type, or the sulfonated portion of an acid sludge containing both sulfonated and polymerized material is then added to the emulsion slowly while the same is agitated, preferably by circulation from the treater through a suction pump and back into the treater. The introduction of the sludge and subsequent circulation of the mixture may take fromone-half to two and one-half hours, depending upon the characteristics of the material. The sulfonated acid sludge employed should be a sulfonated sludge obtained by treatment of the low boiling point distillates of petroleum with sulfuric acid, that is to say, preferably the sludge should be one from the treatment of distillates of lower boiling point than lubricating oil stock, and is preferably the sludge obtained from the treatment of kerosene or lamp oil distillates wherein the kerosene or lamp oil distillate is treated with hot, concentrated or fuming sulfuric acid. Sludges from the treatment of gasoline or motor fuels generally contain no sulfonated products and hence are not of value in the process. The proper amount of sludge for the reaction is .570 of the volume of emulsion treated, and for proper results should not be substantially greater than 1% by volume.

After the completion of the addition of the sludge, the agitation of the mixture is stopped, and the mass allowed to settle or stratify in the treater for a period of about eight to twenty-four hours, depending upon the nature of the crude oil emulsion, the amount of sludgeused and the temperature of the oil during treatment. The water separated may be drawn off as fast as settled or when settling is complete. The crude oil free of the water is then cooled and may be pumped to storage.

As an example of the above described method of demulsifying crude oil emulsions, an emulsion containing from 10% to 22% water has been reduced to one containing .1% to .4:% water by the treatment of .5% per Volume of sulfuric acid sludge derived from the treatment of California or naphthenic base lamp oil distillates with hot, concentrated or fuming sulfuric acid.

While the method of demulsifying emulsions herein described in detail for the purpose of illustrating the invention is well adapted to accomplish the objects of the in vention, it is not intended to limit the invention to the specific details described, as modifications may be made without departing from the spirit of the invention. The invention is therefore not limited to the specific embodiment described, but is of the scope of the appended claims.

I claim 1. A method of dehydrating mineral oil emulsions, which comprises adding to the emulsion sulfonated sludges obtained from refining mineral oils, of a gravity between that of lubricating oil and gasoline, with sulfuric acid, and heating the mixture to between 150 and 200 F.

2. The method of treating emulsions of mineral oils and water which comprises adding to the emulsion 1% or less of a sulfonated sludge obtained from refining lamp oil distillateswith sulfuric acid, and heating the mixture to a temperature between 150 and 200 F.

3. The method of dehydrating mineral oil emulsions, which comprises adding to the emulsion substantially .5% per volume of a sulfonated sludge obtained from refining lamp oil distillates with fuming or concentrated sulfuric acid and heating the mixture to '17 5 F.

4. The method of dehydrating mineral oil emulsions which comprises adding to the emulsion sulfonated sludge derived from refining lamp oil distillates, and heating the mixture.

Signed at San Francisco, Calif, this 2nd day of June, 1925.

RALPH A. HALLORAN. 

